Posted
by
CowboyNealon Friday August 19, 2005 @05:54AM
from the now-lay-me-some-sugar dept.

Rei writes "Researchers at the University of Texas at Dallas have developed the highest quality nanotube sheets to date (the team previously set strength records with polymer-nanotube composites). Producable at a rate comparable to commercial wool spinning, the transparent cloth has exceedingly high conductivity, flexibility, has huge surface area to volume ratios, can potentially be made into very effective OLEDs and thin-film photovoltaic cells, and outperforms even our best bulk materials (such as Mylar and Kevlar) at strength normalized to weight. It strongly absorbs microwaves for localized heating (leading to applications in seamless microwave welding of sections and even windshield warming), changes conductivity little over a wide temperature range (very useful in sensors), and is expected to be used in commercial applications very soon. The research should even be expandable to artificial muscles! To head people off, while the exact tensile strength is not listed, it sounds like it is still far from the >100 GPa needed for a space elevator. Anyways, here's to process advancements!"

I'd like to see these sort of things geared up with 'smart' nanotechnology to make 'smart' cords and stuff like that, imagine a highly conductive wire that provided +, - and ground and detangled itself, or melted into a pool and you just pulled cord out of it, all detangled or bent into whatever shape you want.

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The act of dying; death.
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A pathological condition of a body part, an organ, or a system resulting from various causes, such as infection, genetic defect, or environmental stress, and characterized by an identifiable group of signs or symptoms.

with further tweaking, their nanotube sheets may be useful for building a space elevator tether. They're planning to put the sheets to the test by entering the Spaceward Foundation's Elevator:2010 contest.

Emphasis mine. Seems to suggest that they think they're not too far away from it, so you're not totally off the mark, but we all know that the last few tweaks can be the bit that don't work, relegating this to other uses...

I remember a meeting of the Chicago Society for Space Settlement* at the Adler Planetarium back in 1978 where space elevators were discussed. Even back then, they knew that carbon-fibers were about the only material that could potentially be strong enough.It's taken a very long time to get here (I was just a kid at the time), and I pretty much have always dismissed the idea of space elevators, but it's kinda neat to see that the concept is evolving along the same vein as over two decades ago.

This month's IEEE Spectrum [ieee.org] features an article [ieee.org] by Bradley Edwards who studied the near-term feasibility of a space elevator under a grant from NASA. His conclusion is that it could be accomplished in as little as 10-15 years and for as "little" as $10B (meaning little enough that there are several individuals on Earth who could fund it privately). Of course, the major technological limitation is the nanotubes. He suggests "spun" nanotubes (like yarn) or nanotube composites (and he contends that if one of these broke near the top, it would not be the end of life as we know it -- it's a ribbon that would loft gently down to Earth and burn up in the atmosphere). He even addresses storms, terrorism and space-borne threates. It's a good article and somewhat technical (written for engineers). His conclusions are quite credible, and probably more informed than your average Slashdot debate.

And it has absolutely nothing to do with the technology. It's all about the economics.A space elevator is going to require a truly civilisation shaking level of investment by a country. Then, once it's built that investment has to be amortized over it's lifetime, but wait, it only has two end points and it takes a certain amount of time to load and unload a vehicle of cargo and passengers, it takes a certain amount of time to travel the distance up to orbit. These two fundamental physical limitations will m

The issue is maximum payload, not how many vehicles. The "best" designs so far, that is, the ones that envisage a "safe" elevator that, if cut at the top, will not cause the end of civilization as we know it, can only carry a few tens of pounds of weight. That's a total, not a per-vehicle value. And that small wieght has to travel a distance of over 50,000 miles. You can imagine the time that'll take. Realistically, we're looking at over a week for that small amount of mass to travel the entire length of th

That's simply not true. Read the calculations done by Edwards. Basically, the more affordable the elevator is is almost completely premised on one technological factor: how strong your ribbon is per unit weight. Nobody is proposing building a space elevator with, say, a 10 GPa ribbon, because the launch cost for even a preliminary ribbon. On the other hand, if you have a 120 GPa ribbon, the launch cost is trivial. Yet, both hold the same amount of payload - one is just the tiniest fraction of the total

Edwards declares two as "preferable", one exclusively up and the other exclusively down, and provides no means for power exchange between them. He also doesn't study down climbers, which have different requirements (braking and dissipating the braking energy, plus different strains on the tether)There is a big difference between an up-only cable and an up-down cable - up-down allows for easy energy exchange, better utilization of cable bearing strength, and lower capital costs (than two separate cables), bu

Paragraph two is mostly right anyway.First one is wrong regarding total payload mass. I'd do math to refute the statement, but it has already been done. http://trs.nis.nasa.gov/archive/00000535/ [nasa.gov]

And yeah, the travel time will likely be few days. So what? You can get to LEO in a matter of hours once everything has been built out and systems put in place to deal with any whiplash effects that jumping off before the steady-state altitude.

And it isn't 50K miles to Geo -- it is about 24K miles. I point this out s

Does this mean I can soon have a solar powered bulletproof jacket that enhances my strength, protects me from cell phone emissions, and displays DVDs?

Maybe, but with a description like this...

Producable at a rate comparable to commercial wool spinning, the transparent cloth has exceedingly high conductivity, flexibility, has huge surface area to volume ratios, can potentially be made into very effective OLEDs and thin-film photovoltaic cells, and outperforms even our best bulk materials (such as Mylar an

I know tfa says that it will be efficient, but does that take the cost into perspective? It's not unusual to hear about a new idea that is totally ground braking in several fields, then the research on the commercial fades out, because they find out that it's too pricey. A lot of products was that way in the beginning. Just look at LCD screens etc.

Well. That being said. This sound awesome, I'd like to see it developed...

Cost isn't determined in the lab where the stuff is invented at the time of invention - it's worked out later when it becomes clear that there is more than one way to make something and the best way can be taken advantage of. The first few transistors cost a fortune each to produce, as did aluminium for the first few years. We make both in a different fashion now to the first processes used to make them.

According to this article [usatoday.com], Andrew Barron (Rice University) seems to think we could see this technology used in Formula One racing cars, as early as next season. Although he's probably being a little optimistic, something like a Formula One team would certainly have the sponsors to experiment with tech like this, and develop cheaper manufacturing processes (if possible).

There is no place on a f1 car to "test" them out. Considering that f1 cars produce more then twice there weight in downforce they would not want to use them on the wings. If a car is going around a corner and suddenly a wing rips apart then that car is now going into a wall. Not safe.

The engineers that work with composite material in formula 1 are some of the best in the world. They use carbon material for the housing of the transmission instead of metal. Well they really made it half metal / half c

Yes, it's producable at a certain rate- but what about the cost? Is it economically feasible?
Unfortunate about the space elevator. Looks like the highest we've gone is 63 GPa (http://en.wikipedia.org/wiki/Tensile_strength [wikipedia.org])

In the year 2000, the US wool-making industry produced 46.5 million pounds of wool, averaging out to 3.875 million pounds per month. Obviously the rates of wool production vary greatly with the season. In fact [woolgrowers.org], more than half of American-produced wool is shorn

The article stated the goal was 100 GPa (gigapascals...a measure of stress) tensile strength. The parent mentions the highest measured strength to date comes from a single-walled nanotube that bore 63 GPa (double-walled will theoretically hold more). To give you a comparison, I've pulled ultimate tensile strengths of common materials from matweb.com [matweb.com] (note these are in MPa, not GPa, so the goal is 100,000 MPa)

Yeah, I'm going to have a microwave generator going in my car, aiming the the windshield, just to warm it up.

Don't be silly. It'll just use the ambient microwave radiation we're pouring out now for communications. I'm more worried that with the windshield absorbing all the microwaves my coffee will no longer stay warm in the car.

Funny but the article I read talked about using the nanofabric to Weld sheets of Plexiglas together and for putting in a windshield as an antenna and for windshield warming. For the Windshield warming application it was being used as a simple conductor... you know the tiny little wires you spoke about.

The reason why nanotube composites don't end up being nearly as strong as nanotubes is that nanotubes are very slippery inside of a composite, so once force is applied, it doesn't transfer through the interface and the ultimate tensile strength is primarily determined by the composite.

In this case, when they are weaving fibers together, the weakness in tensile strength will come from the interface between linked nanotubes which will have a tensile strength many orders of magnitude than that of an individual tube.

"...and is expected to be used in commercial applications very soon...",Hmmm, hasn't that been the case for the past decade? That's what my inner cynic says, anyway. Just like the fuel cell revolution, not to mention the nuclear fusion revolution.

If it absorbs microwaves and heats up, it will be visible to infrared.

Ah, anything that absorbs microwaves will heat up. Conservation of energy kind of makes this the case for all materials. The amount of energy hitting a plane from radar is pretty damn small so I doubt it would emit a measureable amount of IR. It isn't like you fly these planes in a microwave.

WTF is Strength normalized to weight?Specific strength is the term they are looking for, second it is normalized to mass, not weight.

Maybe they were trying to target a nonscientific audience. To Joe sixpack Specific strength means nothing, and weight is the same thing as mass(assuming Joe has a vaguely idea about what the word mass means)

Strength normalized to weight is exactly what its name would imply. "Specific strength," not being a very common term, would have needed to be said as, "Specific strength, which is strength normalized to weight..." I'm personally glad they saved the reader the time.

According to the Science [sciencemag.org] article [sciencemag.org](subscription required) abstract [sciencemag.org] a stack of 18 sheets had a strength of 465MPa/(g/cm^3) (high strength steel listed as 125 MPa/(g/cm^3)).

I'm no chemist or engineer, I don't know what potential carbon nanotubes have or don't have but whenever I read an article that seems to promise everything, I figure it is about 95% hyperbole and wishful thinking.I'm pleased to see that these things are getting ready to move into a sort of production phase but really wonder what applications they will find themseves in? If some conventional prduction method produces a product of acceptable quality, I don't see carbon nanotubes making much of a dent in thes

I'm no chemist or engineer, I don't know what potential carbon nanotubes have or don't have but whenever I read an article that seems to promise everything, I figure it is about 95% hyperbole and wishful thinking.

I am a chemist, I work in the "nanotechnology" field, and I have spent time in Engineering/MS labs making OLEDs, PV cells, and other thin film devices. Many of "us" consider nanotubes to be the only viable "nanotechnology" at the moment because of the fact that they can be used by spraying thin layers, making entangled sheets, or other easy-to-commercialize methods of preparation. As for the hybperbole, I think the fact that you're reading an article on MSNBC should give you a clue : ) If you read the Science article they make essentially none of the claims present in the MSNBC article. In fact all they really claim is a new method for preparing NT sheets that is way better than the current methods used for preparing NT 'paper' (it really looks and feels like paper).

Yes, nanotubes are cool. Yes, they conduct electricity. Yes, they emit white light in an OLED configuration. I'm not 100% sure where they're getting the artificial muscle thing, but from what I've read (from peer reviewed journals) don't hold your breath - but I'm no expert there. What generally happens here is the inventors like to hype their discovery up (in this case a method for preparing better NT sheets) as much as possible, but in "science speak". That is, this "may be used for ___" or "has the potential for ___" and then they rattle off stuff NTs can be used for which gets all mixed up in the in article. In this case NT sheets are nothing new and most of what they're claiming has been done before (IBM even got light out of a single NT, far more impressive if you ask me), but they're doing it better with higher quality NT sheets. When it was discovered that poly(aniline) had great mechanical properties as well as interesting "chemical switching" and conductive properties there were people that were sure it was going to be used in planes, clothes, computers... You name it. Too bad it is deliquescent - D'Oh. I can't remember whether this happened before or after the discovery that poly(acetylene) had a high tensile strength and people were claiming space elevators, lightweight electric motors, etc etc. Too bad it catches fire in air in its conductive form - D'Oh D'Oh.

At the end of the day this is another step towards some real nanotechnology applications, but you're reading about it because the editors at Science decided it was worth publishing. Only in the Science article they include all the references to the past work that made it possible:) Oh, and the microwave thing is neat because the NTs will spark like crazy in your microwave oven. So will graphite, which you can try at home if you like... If you don't know NTs are essentially "rolled up" graphite sheets, so they share a lot of common properties.

Here is the abstract:

Individual carbon nanotubes are like minute bits of string, and many trillions of these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per minute by cooperatively rotating carbon nanotubes in vertically oriented nanotube arrays (forests) and made 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of sheets of high-strength steel. These nanotube sheets have been used in laboratory demonstrations for the microwave bonding of plastics and for making transparent, highly elastomeric electrodes; planar sources of polarized broad-band radiation; conducting appliqués; and flexible organic light-emitting diodes.

Okay it looks like this could be used anywhere that you currently use Carbon Fiber. I can hardly wait.Super strong light weight helmets.Homebuilt aircraft.Bicycles.It just goes on and on.The fact it is transparent, conductive, and absorbs microwaves makes me think that we will see a lot of it uses for RAM coatings on ships and aircraft.I can also see it being used for anti rf wall paper and and windows in secure buildings.All in all very cool.

... With this method they can produce nanotube sheets at up to seven meters per minute,...

Assuming the product eventually exceeds 100 GPa, at this rate it would take over 27 years to produce a 100,000 km ribbon in one piece. Since that timescale would be impractical, I figure they should aim for at least a meter per second, which would allow them to do it in a little over three years instead. On the other hand, they could also, for example, set up 30 production lines to work at the current speed, run them all for about a year and then glue the segments together using the extra length for overlap. However, that would add extra volume and make it heavier (remember that the first ribbon has to go up on a rocket).

You quoted "convert a chemical energy supply into mechanical work with even more efficiency than a car engine."

Is there any common direct conversion of chemical energy to mechanical other than the internal combustion engine?

I guess coal-, gas- and oil-fired power plants convert chemical energy to mechanical (and then to electrial) but those aren't very portable. I also don't know whether any of them are internal-combustion on a grand scale or how efficient they are.

How big are your bucks? A space elevator will cost trillions. It'll require thousands, maybe tens of thousands of individual lifts to pay for it. In the meantime, rocket launches are just getting cheaper and cheaper. The Russians and commercial operations like Sea Launch can launch for a miniscule fraction of the cost of a space elevator.

You're probably trolling using a phrase like "will always be cheaper" but since the moderators seem to think your post is serious I'll bite.Launch 100 rockets at 100 bucks per rocket and you've paid $10,000. Launch 100 elevators at at $1 per use and you've paid $100. Point is, which method is cheaper depends on the relative costs of the two methods.

Space Shuttles run $1 billion per launch. Since we don't know how much the elevator will cost to build or operate, $1 per launch is as good a number as any right

Umm, surely this must be totally over-simplifying what they -really- do..

Nope. I saw this presented last month at an Air Force program review, and it is exactly what they say. For example, they showed pictures of 1 m long ribbons, where the length was limited by the length of the postdoc's arm who manually pulled the sheets from the nanotube "forest".

A strength-boosting, bulletproof, super-light-weight bodysuit that can change colour and styles, doubles up as a solar battery, washes itself, heats itself up, cools you down, lights up or darkens things, temporarily blinds and electrocutes hostiles (causing paralysis), cooks food, has jetpack-like capabilities to take you places, remembers everything that happens to it and can replay it (like how much pressure in what places occur when you are hugged), has an in-built calculator, browser and email client,

Super-cheap nanotubes? About fucking time. We've been hearing about nanotubes for years, their possible use in computers, all their various other properties... It certainly took them long enough to discover a cheap way to make them.

Of course, if you had been part of the effort, it would've happened twice as fast. But you obviously had other priorities, and I'm sure I speak for all of us here when I express my deep appreciation for taking a little of your precious time to share your insight with Slashdot.